Midrash sur La Genèse 13:3

... R’ Shimon bar Aba said in the name of R’ Yochanan: any where that it says ‘and it was’ (vayehi) it indicates distress and joy. If it is distress there is no distress like it and if it is joy there is no joy like it. R’ Shmuel ben Nachmani came and split the teaching in half. Anywhere that it says ‘and it was’ (vayehi) indicates distress, ‘and it will be’ (v’haya) indicates joy…The brought a challenge from this verse “…and he was [there] (v’haya) when Jerusalem was taken.” (Jeremiah 38:28) He said to them: this is still a cause of joy because on that very day Israel received full payment for their sins. As R’ Shmuel ben Nachmani said: Israel received full payment for their sins on the day the Holy Temple was destroyed, as it says “Your iniquity is finished, O daughter of Zion…” (Lamentations 4:22)